<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        html *{
            padding:0;
            margin:0;
        }

        .layout article div{
            min-height: 100px;
        }
    </style>
</head>
<body>
    <section class="layout float">
        <style media="screen">
            .layout.float .left{
                float: left;
                width:300px;
                background-color: red;
            }
        </style>
        <article class="left-right-center">
            <div class="left"></div>
            <div class="right"></div>
            <div class="center">
                <h1>浮动解决方案：</h1>
                1.中间部分
                2.中间部分
            </div>
        </article>
    </section>
</body>
</html>